In recent years, with the wide spread use of a digital still camera, a digital video camera, and a mobile phone with a camera, occasions in which an individual person captures and stores a content item such as an image, audio, and video have increased significantly. In addition, communication is actively conducted, by sharing such a content item with a friend or a member of family, to share one's experience, recommend a travel destination, or have fun talking about one's memory.
Such content items are managed using photographs on which the content items are printed, video tapes, and the like. However, more and more content items can be managed electronically today, using a personal computer connected to a network or a content managing apparatus. The sharing of an electronic content item has been conducted widely due to significantly low costs for management and the high-level convenience.
On the other hand, a managed content item is shared, in some cases, with a partner user without concerning the interest of the partner user, for example. This brings about the possibility of annoying the partner user by the sharing of a content item which the partner user has no interest in viewing. It is therefore desirable, for both of the users; the user who is a sharer of the content item and the user who is a recipient of the content item, that the content item is managed properly between users who are interested in the content item.
As a conventional technique for knowing a user's interest, there is a technique of collecting history of a program viewed by a viewer of a television program (see Patent Literature 1, for example).
In addition, there is a technique of collecting comments from viewers of a television program and classifying the viewers according to the viewer's preferences (see Patent Literature 2, for example).